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Universal Dried Blood Spot Screening for Congenital Cytomegalovirus: A Slovenian National Implementation Pilot
Nika Eržen1,2, Jernej Kovač2,3, Barbka Repič Lampret3
1Department of Neonatology, University Children's Hospital, University Medical Centre Ljubljana, Bohoričeva 20, 1000 Ljubljana, Slovenia.
Insights
Universal screening for congenital cytomegalovirus (cCMV) using dried blood spots is feasible in newborns. This approach significantly increases detection rates compared to selective screening, identifying more infants with this common infection.
Area of Science:
- Neonatal screening
- Infectious disease diagnostics
- Public health
Background:
- Congenital cytomegalovirus (cCMV) is the leading cause of congenital infection and a major contributor to sensorineural hearing loss and neurodevelopmental issues.
- Current selective screening methods result in many affected infants remaining undiagnosed.
Purpose of the Study:
- To assess the feasibility and diagnostic yield of universal dried blood spot (DBS)-based screening for cCMV within Slovenia's national newborn screening program.
- To compare universal screening with historical clinical case ascertainment.
Main Methods:
- A prospective national pilot study involving 5556 newborns screened using DBS-based polymerase chain reaction (PCR).
- Screen-positive infants underwent confirmatory urine PCR and clinical evaluation within 21 days.
- Comparison with historical registry data for clinical case ascertainment.
Main Results:
- A birth prevalence of 1.80 per 1000 live births was identified, significantly higher than the 0.09 per 1000 from historical data.
- None of the 10 confirmed cCMV cases were clinically suspected at birth, and all passed initial newborn hearing screening.
- Six infants with symptomatic cCMV received treatment with valganciclovir.
Conclusions:
- Universal DBS-based cCMV screening is feasible within existing newborn screening infrastructure.
- Selective clinical detection pathways significantly under-ascertain cCMV cases.
- Universal screening offers a more effective strategy for identifying infants with cCMV, enabling timely intervention.
Abstract:
Congenital cytomegalovirus infection (cCMV) is the most common congenital infection and an important cause of sensorineural hearing loss and neurodevelopmental impairment, yet many affected infants remain undetected under selective screening approaches. We conducted a prospective national pilot study to evaluate the feasibility and diagnostic yield of universal dried blood spot (DBS)-based screening for cCMV within the Slovenian newborn screening program. DBS samples collected within 72 h of life were tested by polymerase chain reaction (PCR), and screen-positive newborns underwent confirmatory urine PCR within 21 days together with standardized clinical evaluation. Among 5556 screened newborns, 13 (0.23%) screened positive and cCMV was confirmed in 10, corresponding to a lower-bound birth prevalence of 1.80 per 1000 live births (95% confidence interval, 0.98-3.31), because confirmatory testing was limited to DBS-positive newborns. None of the confirmed cases were clinically suspected at birth, and all passed newborn hearing screening. Six infants met protocol-defined criteria for symptomatic cCMV and received valganciclovir. Historical registry-based clinical case ascertainment in Slovenia corresponded to 0.09 detected cases per 1000 live births. These findings demonstrate the feasibility of universal DBS-based cCMV screening within an established newborn screening infrastructure and suggest substantial under-ascertainment under selective clinical detection pathways.
